The present invention relates to the connection of submerged conduits and, more particularly, to a method and apparatus for interconnecting such conduits in a manner to substantially isolate each conduit from forces experienced by the other.
Establishing connections between submerged conduits has been a continuing problem over the years, typically requiring intricate coupling assemblies and/or the substantial use of divers to accomplish the connection. Additionally, where one of the conduits is relatively fixed (e.g., a riser secured to an underwater tower, well head, etc.), rather than being simply the terminal portion of an elongated pipeline, the problem of alignment of the two conduits in order to make the appropriate connection therebetween is further complicated. With fixed conduits, of course, even after the complicated and expensive process of connecting the pipeline thereto, potentially damaging forces may be transmitted to the fixed conduit from the pipeline (e.g., thermal expansion or contraction of the pipeline). Such forces present a danger of loosening the connection established between the pipeline and the fixed conduit, damaging the fixed conduit or the structure to which it is secured, or even causing a shift in the position of the structure to which the fixed conduit is secured. The improved pipeline connection technique of Lochridge et al U.S. Pat. No. 3,599,436 (issued Aug. 17, 1971 and owned by the assignee of the present invention), involving the welding of two conduits in an underwater work chamber, does not, of itself, provide isolation of the fixed conduit from thermal expansion of the pipeline.